The invention described herein was made in the performance of official duties by employees of the Department of the Navy and may be manufactured, used, licensed by or for the Government for any governmental purpose without payment of any royalties thereon.
The invention relates generally to life support for underwater habitable environments (e.g., habitats, submersibles, submarines, etc.), and more particularly to method and system for supplying breathable gas for an underwater habitable environment using the surrounding water environment to remove carbon dioxide from respired gases within the underwater habitable environment.
A recurring problem for designers of closed-circuit breathing apparatus used in underwater habitats is the removal of metabolically-produced carbon dioxide from the breathing gas. Traditional methods include the use of dry chemical beds, regenerative cycles, or complex physical techniques. All these methods, however, have drawbacks. Expendable, dry chemicals must be replenished and disposed of at considerable trouble and expense on a frequent basis, and are therefore not suitable for long-term deployment applications. Regenerative cycle systems use small amounts of expendables, but require large amounts of energy for operation. Physical methods typically use fragile and expensive membranes for operation, and have proven impractical in an operational environment for personal life support systems.
Accordingly, it is an object of the present invention to provide a method and system that can supply breathable gas lo an underwater habitat.
Another object of the present invention is to provide a closed-circuit method and system for supplying breathing gas to a submerged underwater habitat.
Still another object of the present invention is to provide a method and system that can supply breathable gas to an underwater habitat without the use of chemically-based carbon dioxide absorbents.
Yet another object of the present invention is to provide a method and system that can supply breathable gas to an underwater environment in a simple, reliable, efficient and safe manner.
Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings.
In accordance with the present invention, a system and method are provided for supplying breathable gas to an underwater habitat submerged in water. A flow of respired gas that includes metabolically-produced carbon dioxide is extracted from the underwater habitat. The flow of respired gas is mixed with water from the surrounding environment. As a result of such mixing, carbon dioxide in the respired gas is substantially absorbed by the water while a first gas is allowed to escape from the mixing water. Moisture in the first gas is filtered out to produce a breathable gas which is then introduced back into the underwater habitat.